Birefringent lens material for stereoscopic image display device and method for producing birefringent lens for stereoscopic image display device

ABSTRACT

The present invention provides a birefringent lens material for a stereoscopic image display, the birefringent lens material containing two or more liquid crystal compounds each having at least one polymerizable functional group, a birefringent lens for a stereoscopic image display, the birefringent lens being formed by using the lens material, and a method for producing a birefringent lens for a stereoscopic image display using the lens material. The birefringent lens material for a stereoscopic image display and the birefringent lens for a stereoscopic image display of the present invention are good in terms of optical characteristics, durability, and productivity, in particular, productivity. The method for producing a birefringent lens for a stereoscopic image display of the present invention has good productivity.

TECHNICAL FIELD

The present invention relates to a birefringent lens material used for astereoscopic image display and a method for producing a birefringentlens for a stereoscopic image display.

BACKGROUND ART

A stereoscopic image display provides a sense of depth by individuallysending substantially two-dimensional images to the right eye and theleft eye of a person, allowing the images to be integrated in the brain,and allowing the integrated image to be stereoscopically viewed. Forthis purpose, it is necessary to individually form images for generatinga parallax in advance and to correct the images when the images are sentto the corresponding eyes, or it is necessary to separate atwo-dimensional image into an image to be viewed by the right eye and animage to be viewed by the left eye.

In the method for separating a two-dimensional image, it is notnecessary to wear polarized glasses or the like for correcting an imageand thus a stereoscopic image can be viewed by the naked eye. Examplesof the method for separating a two-dimensional image include a methodusing a lenticular lens and a parallax barrier method. The lenticularlens is a lens that separates an image into two images by determiningthe width of a certain image that can be viewed by one eye usingrefraction by the lens. As the lenticular lens, a birefringent lenshaving a shape in which semicylinders are arranged in a line is used forgenerating a parallax.

Regarding a characteristic required for the lenticular lens, a smallchange in the refractive index with respect to the temperature change isrequired in order to use the lenticular lens in a wide range ofenvironments. To meet this requirement, a technique has been proposed inwhich a cured liquid crystal polymer is used as a material of abirefringent lens (refer to PTL 1 and NPL 1).

However, many different types of liquid crystal polymers exist, and inthe case where a cured liquid crystal polymer is simply used as amaterial of a birefringent lens without studying the material in detail(refer to PTL 1), problems in terms of optical characteristics,durability, productivity, etc. of the lens may occur. A technique inwhich a bifunctional liquid crystalline monomer is used as abirefringent lens material is disclosed (NPL 1). However, this materialhas problems in terms of optical characteristics and productivity, andthus the application of this material as a birefringent lens materialcomposed of a liquid crystal polymer has not proceeded.

CITATION LIST Patent Literature

-   PTL 1: Japanese Unexamined Patent Application Publication    (Translation of PCT Application) No. 2004-538529

Non Patent Literature

-   NPL 1: IDW '04, pp. 1495 and 1496

SUMMARY OF INVENTION Technical Problem

An object of the present invention is to provide a birefringent lensmaterial used for a stereoscopic image display and a birefringent lensfor a stereoscopic image display, the birefringent lens material andbirefringent lens having good optical characteristics, durability, andproductivity, in particular, productivity. In addition, another objectof the present invention is to provide a method for producing abirefringent lens for a stereoscopic image display, the method havinggood productivity.

Solution to Problem

The inventors of the present invention conducted intensive studies onvarious liquid crystal monomers used in a birefringent lens. As aresult, it was found that, by using a birefringent lens material inwhich the number of types of particular liquid crystal monomers isincreased, birefringent properties of the material can be changed,sufficient durability can be obtained, and curing at room temperaturecan be realized. This finding resulted in the completion of the presentinvention.

Specifically, the present invention provides a birefringent lensmaterial for a stereoscopic image display, the birefringent lensmaterial containing two or more liquid crystal compounds each having atleast one polymerizable functional group, and a birefringent lens for astereoscopic image display, the birefringent lens being formed by curingthe lens material. In addition, the present invention provides a methodfor producing a birefringent lens for a stereoscopic image display, themethod including applying the lens material onto an alignment layer thathas been subjected to an alignment treatment in a uniaxial direction;and forming the resulting coating film into a lens shape by conductingcuring with ultraviolet light.

Advantageous Effects of Invention

According to the birefringent lens material for a stereoscopic imagedisplay of the present invention and the birefringent lens for astereoscopic image display produced by using the lens material, goodoptical characteristics, good durability, and good productivity can beachieved by increasing the number of types of particular liquid crystalmonomers.

In addition, the method for producing a birefringent lens for astereoscopic image display using the above material can suppress thegeneration of alignment defects of a liquid crystal monomer and has goodproductivity.

DESCRIPTION OF EMBODIMENTS

A birefringent lens material for a stereoscopic image display of thepresent invention contains two or more liquid crystal compounds eachhaving at least one polymerizable functional group. From the standpointof durability, the liquid crystal compounds each having at least onepolymerizable functional group are preferably two or more liquid crystalcompounds each having at least two polymerizable functional groups. Theliquid crystal compounds each having at least two polymerizablefunctional groups are contained in an amount of preferably 10% to 95% byweight, and more preferably 15% to 90% by weight. In addition, theliquid crystal compounds having polymerizable functional groupspreferably have the same mesogenic group or the same mesogenitysupporting group.

Each of the liquid crystal compounds having at least one polymerizablefunctional group is preferably a compound represented by general formula(1):[Chem. 1]P-(Sp)_(m)-MG-R¹  (1)(where P represents a polymerizable functional group; Sp represents aspacer group having 0 to 18 carbon atoms; m represents 0 or 1; MGrepresents a mesogenic group or a mesogenity supporting group; and R¹represents a halogen atom, a cyano group, a thiocyanate group, a hydroxygroup, an NCO group, an OCN group, or an alkyl group having 1 to 18carbon atoms, the alkyl group may be substituted with at least oneselected from halogen atoms, a cyano group, and a hydroxy group, and oneCH₂ group or two or more non-adjacent CH₂ groups present in this groupmay each be independently substituted with a divalent organic group suchas —O—, —S—, —NH—, —N(CH₃)—, —CO—, —COO—, —OCO—, —OCOO—, —SCO—, —COS—,—CH═CH—, or —C≡C— in such a manner that oxygen atoms are not directlybonded to each other, or R¹ represents a structure represented bygeneral formula (1-a):[Chem. 2]-(Sp)_(m)-P  (1-a)

(where P represents a polymerizable functional group, Sp represents aspacer group having 0 to 18 carbon atoms, and m represents 0 or 1).

The birefringent lens material for a stereoscopic image display of thepresent invention preferably has a transition temperature from a solidphase to a liquid-crystalline phase of −10° C. or lower, and atransition temperature from a liquid-crystalline phase to a liquid phaseof 50° C. or higher. The transition temperature from a solid phase to aliquid-crystalline phase is preferably 0° C. or lower, and thetransition temperature from a liquid-crystalline phase to a liquid phaseis preferably 40° C. or higher.

The birefringent lens material for a stereoscopic image display of thepresent invention is preferably a material that can be polymerized at aroom temperature of 20° C. to 30° C.

a) (Liquid Crystal Compound Having One Polymerizable Functional Group)

In the birefringent lens material for a stereoscopic image display ofthe present invention, a liquid crystal compound having onepolymerizable functional group exhibits liquid crystallinity alone or ina composition containing other liquid crystal compounds. The liquidcrystal compound is not particularly limited as long as the compound hasone polymerizable functional group, and well-known, commonly usedcompounds can be used.

Examples thereof include rod-shaped polymerizable liquid crystalcompounds having a rigid portion which is called a “mesogen” in which aplurality of structures such as a 1,4-phenylene group and a1,4-cyclohexylene group are connected to each other and a polymerizablefunctional group such as a vinyl group, an acrylic group, or a(meth)acrylic group, the rod-shaped polymerizable liquid crystalcompounds being described in, for example, Handbook of Liquid Crystals(Edited by D. Demus, J. W. Goodby, G. W. Gray, H. W. Spiess, and V.Vill, published by Wiley-VCH, 1998), Kikan Kagaku Sosetsu (Survey ofChemistry, Quarterly) No. 22, Chemistry of liquid crystal (edited by theChemical Society of Japan, 1994), or Japanese Unexamined PatentApplication Publication Nos. 7-294735, 8-3111, 8-29618, 11-80090,11-116538, or 11-148079; and rod-shaped polymerizable liquid crystalcompounds having a maleimide group, the rod-shaped polymerizable liquidcrystal compounds being described in Japanese Unexamined PatentApplication Publication Nos. 2004-2373 and 2004-99446. Among these,rod-shaped polymerizable liquid crystal compounds each having apolymerizable group are preferable from the standpoint that a materialhaving a liquid crystal temperature range including a low temperature ofabout room temperature can be easily prepared.

Specific examples thereof preferably include compounds represented bygeneral formula (1):[Chem. 3]P-(Sp)_(m)-MG-R¹  (1)(where P represents a polymerizable functional group; Sp represents aspacer group having 0 to 18 carbon atoms; m represents 0 or 1; MGrepresents a mesogenic group or a mesogenity supporting group; and R¹represents a halogen atom, a cyano group, a thiocyanate group, a hydroxygroup, an NCO group, an OCN group, or an alkyl group having 1 to 18carbon atoms, the alkyl group may be substituted with at least oneselected from halogen atoms, a cyano group, and a hydroxy group, and oneCH₂ group or two or more non-adjacent CH₂ groups present in this groupmay each be independently substituted with a divalent organic group suchas —O—, —S—, —NH—, —N(CH₃)—, —CO—, —COO—, —OCO—, —OCOO—, —SCO—, —COS—,—CH═CH—, or —C≡C— in such a manner that oxygen atoms are not directlybonded to each other.)

Well-known, commonly used polymerizable functional groups are used asthe polymerizable functional group of the compound represented bygeneral formula (1). Examples of the polymerizable functional groupinclude a vinyl group, an allyl group, a styryl group, a vinyl ethergroup, an allyl ether group, an acrylic group, a (meth)acrylic group, anacrylamide group, a (meth)acrylamide group, a glycidyl group, a glycidylether group, an oxetanyl group, an oxetanyl ether group, a cyanuricgroup, an isocyanuric group, a maleimide group, a maleimide carboxylgroup, a thiol group, a dialkyl fumarate group, an acetylenyl group, anorganosilyl group, and functional groups that can be subjected tocyclopolymerization or ring-opening polymerization. Each of thepolymerizable functional groups may have a substituent such as a halogenatom, a methyl group, or a trifluoromethyl group as long as thepolymerizability is not impaired.

The mesogenic group or the mesogenity supporting group of the compoundrepresented by general formula (1) includes a ring structure and a groupthat connects the ring structure, and is represented by, for example,general formula (1-1):[Chem. 4]—Sp₁-(MG₁-Sp₂)_(n)-MG₂-Sp₃-  (1-1)

(In the formula, MG₁ and MG₂ each independently represent at least onering structure, Sp₁, Sp₂, and Sp₃ each independently represent a singlebond or a divalent organic group, in the case where one ring structurecan function as a mesogenic group or a mesogenity supporting group, nrepresents 0 to 5, and in the case where two or more ring structures canfunction as a mesogenic group or a mesogenity supporting group, nrepresents 1 to 6.)

In general formula (1-1), examples of MG₁ and MG₂ each having at leastone ring structure include well-known, commonly used structures, andspecific examples thereof include the following:

(In the formulae, each structure may have, as at least one substituent,at least one selected from F, Cl, CF₃, OCF₃, a CN group, alkyl groupseach having 1 to 8 carbon atoms, alkoxy groups each having 1 to 8 carbonatoms, alkanoyl groups each having 1 to 8 carbon atoms, alkanoyloxygroups each having 1 to 8 carbon atoms, alkenyl groups each having 2 to8 carbon atoms, alkenyloxy groups each having 2 to 8 carbon atoms,alkenoyl groups each having 2 to 8 carbon atoms, and alkenoyloxy groupseach having 2 to 8 carbon atoms.)

In general formula (1-1), Sp₁, Sp₂, and Sp₃ are each preferably, forexample, a single bond or a divalent organic group such as —COO—, —OCO—,—COS—, —SCO—, —OCOO—, —CH₂CH₂—, —OCH₂—, —CH₂O—, —OCF₂—, —CF₂O—, —CH═CH—,—CH═N—, —CF═CF—, —N═N—, —C═N—N═C—, —C≡C—, —CH═CHCOO—, —OCOCH═CH—,—CH═CHCOS—, —SCOCH═CH—, —CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—,—OCOCH₂CH₂—, —CONH—, —NHCO—, or an alkylene group which has 2 to 10carbon atoms and which may have a halogen atom.

More specifically, preferable are compounds represented by generalformula (1) wherein Sp represents a single bond or an alkylene group(where the alkylene group may be substituted with at least one selectedfrom halogen atoms and CN, and one CH₂ group or two or more non-adjacentCH₂ groups present in this group may each be independently substitutedwith —O—, —S—, —NH—, —N(CH₃)—, —CO—, —COO—, —OCO—, —OCOO—, —SCO—, —COS—,—CONH—, —NHCO—, —CH═CH—, or —C≡C— in such a manner that oxygen atoms arenot directly bonded to each other), and MG is represented by generalformula (1-b):[Chem. 7]—Z0-(A1-Z1)_(n)-A2-Z2-A3-Z3-  (1-b)

(where A1, A2, and A3 each independently represent a 1,4-phenylenegroup, a 1,4-cyclohexylene group, a 1,4-cyclohexenyl group, atetrahydropyran-2,5-diyl group, a 1,3-dioxane-2,5-diyl group, atetrahydrothiopyran-2,5-diyl group, a 1,4-bicyclo[2.2.2]octylene group,a decahydronaphthalene-2,6-diyl group, a pyridine-2,5-diyl group, apyrimidine-2,5-diyl group, a pyrazine-2,5-diyl group, athiophene-2,5-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diylgroup, a 1,4-naphthylene group, a 1,5-naphthylene group, a1,6-naphthylene group, a 2,6-naphthylene group, a phenanthrene-2,7-diylgroup, a 9,10-dihydrophenanthrene-2,7-diyl group, a1,2,3,4,4a,9,10a-octahydrophenanthrene-2,7-diyl group, abenzo[1,2-b:4,5-b′]dithiophene-2,6-diyl group, abenzo[1,2-b:4,5-b′]diselenophene-2,6-diyl group, a[1]benzothieno[3,2-b]thiophene-2,7-diyl group, a[1]benzoselenopheno[3,2-b]selenophene-2,7-diyl group, afluorene-2,7-diyl group, or the like, and may have, as at least onesubstituent, at least one selected from F, CL, CF₃, OCF₃, a CN group,alkyl group each having 1 to 8 carbon atoms, alkoxy groups each having 1to 8 carbon atoms, alkanoyl groups each having 1 to 8 carbon atoms,alkanoyloxy groups each having 1 to 8 carbon atoms, alkenyl groups eachhaving 2 to 8 carbon atoms, alkenyloxy groups each having 2 to 8 carbonatoms, alkenoyl groups each having 2 to 8 carbon atoms, and alkenoyloxygroups each having 2 to 8 carbon atoms; Z0, Z1, Z2, and Z3 eachindependently represent —COO—, —OCO—, —CH₂CH₂—, —OCH₂—, —CH₂O—, —OCF₂—,—CF₂O—, —CH₂S—, —SCH₂—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CHCOO—, —OCOCH═CH—,—CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—, —OCOCH₂CH₂—, —OCO═COO—, —CONH—,—NHCO—, an alkylene group which has 2 to 10 carbon atoms and which mayhave a halogen atom, or a single bond; and n represents 0, 1, or 2.)

The polymerizable functional group is preferably any of an acrylicgroup, a (meth)acrylic group, an acrylamide group, a vinyl group, avinyl ether group, a glycidyl group, a glycidyl ether group, an oxetanylgroup, an oxetanyl ether group, a maleimide group, a maleimide carboxylgroup, a thiol group, etc. represented by general formulae (P-1) to(P-18):

From the standpoint of productivity, a vinyl ether group, an acrylicgroup, a (meth)acrylic group, a glycidyl group, and a glycidyl ethergroup are particularly preferable.

Furthermore, the liquid crystal compound having one polymerizablefunctional group is preferably a compound selected from the compoundgroup represented by general formulae (3) and (4):

(In the formulae, Z¹ and Z³ each independently represent a hydrogenatom, a halogen atom, a cyano group, or a hydrocarbon group having 1 to18 carbon atoms; Z² and Z⁴ each independently represent a hydrogen atomor a methyl group; t and u each independently represent 0, 1, or 2; vrepresents an integer of 2 to 18; W³ represents a single bond, —O—,—COO—, or —OCO—; A, B, C, D, E, and F each independently represent a1,4-phenylene group, a 1,4-phenylene group in which non-adjacent CHgroups are each substituted with nitrogen, a 1,4-cyclohexylene group, a1,4-cyclohexylene group in which one or non-adjacent two CH₂ groups areeach substituted with an oxygen or sulfur atom, a 1,4-cyclohexenylgroup, a 1,4-bicyclo[2.2.2]octylene group, adecahydronaphthalene-2,6-diyl group, a pyridine-2,5-diyl group, apyrimidine-2,5-diyl group, a pyrazine-2,5-diyl group, a1,2,3,4-tetrahydronaphthalene-2,6-diyl group, a 2,6-naphthylene group,or a 1,4-naphthylene group, and a 1,4-phenylene group and a2,6-naphthylene group that are present in the formulae may each besubstituted with at least one selected from alkyl groups each having 1to 7 carbon atoms, alkoxy groups each having 1 to 7 carbon atoms,alkanoyl groups each having 1 to 7 carbon atoms, a cyano group, andhalogen atoms; Y³, Y⁴, Y⁶, and Y⁷ each independently represent a singlebond, —CH₂CH₂—, —CH₂O—, —OCH₂—, —COO—, —OCO—, —C≡C—, —CH═CH—, —CF═CF—,—(CH₂)₄—, —CH₂CH₂CH₂O—, —OCH₂CH₂CH₂—, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—, or—OCOCH₂CH₂—; and Y⁵ and Y⁸ each independently represent a single bond,—O—, —COO—, —OCO—, or —CH═CHCOO—.)

Exemplary compounds are shown below but are not limited thereto.

(In the formulae, m represents an integer of 2 to 18, n represents aninteger of 0 to 18, and R represents a hydrogen atom, an alkyl grouphaving 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,a carboxyl group, or a cyano group. In the case where any of thesegroups is an alkyl group having 1 to 6 carbon atoms or an alkoxy grouphaving 1 to 6 carbon atoms, the group may be unsubstituted orsubstituted with one or two or more halogen atoms.) These liquid crystalcompounds may be used alone or in combination of two or more compounds.b) (Liquid Crystal Compound Having Two or More Polymerizable FunctionalGroups)

A liquid crystal compound having two or more polymerizable functionalgroups and used in the birefringent lens material for a stereoscopicimage display of the present invention exhibits liquid crystallinityalone or in a composition containing other liquid crystal compounds. Theliquid crystal compound is not particularly limited as long as thecompound has two or more polymerizable functional groups, andwell-known, commonly used compounds can be used.

Examples thereof include rod-shaped polymerizable liquid crystalcompounds having a rigid portion which is called a “mesogen” in which aplurality of structures such as a 1,4-phenylene group and a1,4-cyclohexylene group are connected to each other and polymerizablefunctional groups such as a vinyl group, an acrylic group, or a(meth)acrylic group, the rod-shaped polymerizable liquid crystalcompounds being described in, for example, Handbook of Liquid Crystals(Edited by D. Demus, J. W. Goodby, G. W. Gray, H. W. Spiess, and V.Vill, published by Wiley-VCH, 1998), Kikan Kagaku Sosetsu (Survey ofChemistry, Quarterly) No. 22, Chemistry of liquid crystal (edited by theChemical Society of Japan, 1994), or Japanese Unexamined PatentApplication Publication Nos. 4-227684, 11-80090, 11-116538, 11-148079,2000-178233, 2002-308831, 2002-145830, and 2004-125842; and rod-shapedpolymerizable liquid crystal compounds having a maleimide group, therod-shaped polymerizable liquid crystal compounds being described inJapanese Unexamined Patent Application Publication Nos. 2004-2373 and2004-99446. Among these, rod-shaped polymerizable liquid crystalcompounds having polymerizable groups are preferable from the standpointthat a material having a liquid crystal temperature range including alow temperature of about room temperature can be easily prepared.

Specific examples thereof preferably include compounds represented bygeneral formula (1):[Chem. 57]P-(Sp)_(m)-MG-R¹  (1)(where P represents a polymerizable functional group; Sp represents aspacer group having 0 to 18 carbon atoms; m represents 0 or 1; MGrepresents a mesogenic group or a mesogenity supporting group; and R¹ isrepresented by general formula (1-a):[Chem. 58]-(Sp)_(m)-P  (1-a)

(where P represents a polymerizable functional group, Sp represents aspacer group having 0 to 18 carbon atoms, and m represents 0 or 1).Well-known, commonly used polymerizable functional groups are used asthe polymerizable functional group in general formula (1). Examples ofthe polymerizable functional group include a vinyl group, an allylgroup, a styryl group, a vinyl ether group, an allyl ether group, anacrylic group, a (meth)acrylic group, an acrylamide group, a(meth)acrylamide group, a glycidyl group, a glycidyl ether group, anoxetanyl group, an oxetanyl ether group, a cyanuric group, anisocyanuric group, a maleimide group, a maleimide carboxyl group, athiol group, a dialkyl fumarate group, an acetylenyl group, anorganosilyl group, and functional groups that can be subjected tocyclopolymerization or ring-opening polymerization. Each of thepolymerizable functional groups may have a substituent such as a halogenatom, a methyl group, or a trifluoromethyl group as long as thepolymerizability is not impaired.

The mesogenic group or the mesogenity supporting group in generalformula (1) includes a ring structure and a group that connects the ringstructure, and is represented by, for example, general formula (1-1):[Chem. 59]-Sp₁-(MG₁-Sp₂)_(n)-MG₂-Sp₃-  (1-1)

(In the formula, MG₁ and MG₂ each independently represent at least onering structure, Sp₁, Sp₂, and Sp_(a) each independently represent asingle bond or a divalent organic group, in the case where one ringstructure can function as a mesogenic group or a mesogenity supportinggroup, n represents 0 to 5, and in the case where two or more ringstructures can function as a mesogenic group or a mesogenity supportinggroup, n represents 1 to 6.)

In general formula (1-1), examples of MG₁ and MG₂ each having at leastone ring structure include well-known, commonly used structures, andspecific examples thereof include the following:

(In the formulae, each structure may have, as at least one substituent,at least one selected from F, Cl, CF₃, OCF₃, a CN group, alkyl groupseach having 1 to 8 carbon atoms, alkoxy groups each having 1 to 8 carbonatoms, alkanoyl groups each having 1 to 8 carbon atoms, alkanoyloxygroups each having 1 to 8 carbon atoms, alkenyl groups each having 2 to8 carbon atoms, alkenyloxy groups each having 2 to 8 carbon atoms,alkenoyl groups each having 2 to 8 carbon atoms, alkenoyloxy groups eachhaving 2 to 8 carbon atoms, and general formula (1-a):[Chem. 62]-(Sp)_(m)-P  (1-a)(where P represents a polymerizable functional group, Sp represents aspacer group having 0 to 18 carbon atoms, and m represents 0 or 1).)

In general formula (1-1), Sp₁, Sp₂, and Sp₃ are each preferably, forexample, a single bond or a divalent organic group such as —COO—, —OCO—,—COS—, —SCO—, —OCOO—, —CH₂CH₂—, —OCH₂—, —CH₂O—, —OCF₂—, —CF₂O—, —CH═CH—,—CH═N—, —CF═CF—, —N═N—, —C═N—N═C—, —C≡C—, —CH═CHCOO—, —OCOCH═CH—,—CH═CHCOS—, —SCOCH═CH—, —CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—,—OCOCH₂CH₂—, —CONH—, —NHCO—, or an alkylene group which has 2 to 10carbon atoms and which may have a halogen atom.

More specifically, preferable are compounds represented by generalformula (1) wherein Sp represents a single bond or an alkylene group(where the alkylene group may be substituted with at least one selectedfrom halogen atoms and CN, and one CH₂ group or two or more non-adjacentCH₂ groups present in this group may each be independently substitutedwith —O—, —S—, —NH—, —N(CH₃)—, —CO—, —COO—, —OCO—, —OCOO—, —SCO—, —COS—,or —C≡C— in such a manner that oxygen atoms are not directly bonded toeach other), and MG is represented by general formula (1-b):[Chem. 63]—Z0-(A1-Z1)_(n)-A2-Z2-A3-Z3-  (1-b)

(where A1, A2, and A3 each independently represent a 1,4-phenylenegroup, a 1,4-cyclohexylene group, a 1,4-cyclohexenyl group, atetrahydropyran-2,5-diyl group, a 1,3-dioxane-2,5-diyl group, atetrahydrothiopyran-2,5-diyl group, a 1,4-bicyclo[2.2.2]octylene group,a decahydronaphthalene-2,6-diyl group, a pyridine-2,5-diyl group, apyrimidine-2,5-diyl group, a pyrazine-2,5-diyl group, athiophene-2,5-diyl group, a 1,2,3,4-tetrahydronaphthalene-2,6-diylgroup, a 2,6-naphthylene group, a phenanthrene-2,7-diyl group, a9,10-dihydrophenanthrene-2,7-diyl group, a1,2,3,4,4a,9,10a-octahydrophenanthrene-2,7-diyl group, a 1,4-naphthylenegroup, a benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl group, abenzo[1,2-b:4,5-b′]diselenophene-2,6-diyl group, a[1]benzothieno[3,2-b]thiophene-2,7-diyl group, a[1]benzoselenopheno[3,2-b]selenophene-2,7-diyl group, or afluorene-2,7-diyl group, and may have, as at least one substituent, atleast one selected from F, Cl, CF₃, OCF₃, a CN group, alkyl groups eachhaving 1 to 8 carbon atoms, alkoxy groups each having 1 to 8 carbonatoms, alkanoyl groups each having 1 to 8 carbon atoms, alkanoyloxygroups each having 1 to 8 carbon atoms, alkenyl groups each having 2 to8 carbon atoms, alkenyloxy groups each having 2 to 8 carbon atoms,alkenyl groups each having 2 to 8 carbon atoms, and alkenoyloxy groupseach having 2 to 8 carbon atoms; Z0, Z1, Z2, and Z3 each independentlyrepresent —COO—, —OCO—, —CH₂CH₂—, —OCH₂—, —CH₂O—, —CH═CH—, —C≡C—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—,—OCOCH₂CH₂—, —CONH—, —NHCO—, an alkylene group which has 2 to 10 carbonatoms and which may have a halogen atom, or a single bond; and nrepresents 0, 1, or 2.)

The polymerizable functional group is preferably any of an acrylicgroup, a (meth)acrylic group, an acrylamide group, a vinyl group, avinyl ether group, a glycidyl group, a glycidyl ether group, an oxetanylgroup, an oxetanyl ether group, a maleimide group, a maleimide carboxylgroup, a thiol group, etc. represented by general formulae (P-1) to(P-18):

From the standpoint of productivity, a vinyl ether group, an acrylicgroup, a (meth)acrylic group, a glycidyl group, and a glycidyl ethergroup are particularly preferable.

Furthermore, the liquid crystal compound having two or morepolymerizable functional groups is preferably a compound selected fromthe compound group represented by general formulae (2a) and (2b):

(In the formulae, Z¹⁰ and Z¹¹ each independently represent a hydrogenatom or a methyl group; m and m1 represent 0 or 1; W¹, W¹¹, W², and W¹²each independently represent a single bond, —O—, —COO—, or —OCO—; Y⁰,Y¹, Y², and Y¹¹ each independently represent —COO— or —OCO—; r, r1, s,and s1 each independently represent an integer of 2 to 18; and a1,4-phenylene group present in the formulae may be substituted with atleast one selected from alkyl groups each having 1 to 7 carbon atoms,alkoxy groups each having 1 to 7 carbon atoms, alkanoyl groups eachhaving 1 to 7 carbon atoms, a cyano group, and halogen atoms.)

Exemplary compounds are shown below but are not limited thereto.

(In the formulae, m and n each independently represent an integer of 1to 18; and R represents a hydrogen atom, a halogen atom, an alkyl grouphaving 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms,or a cyano group. In the case where any of these groups is an alkylgroup having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbonatoms, the group may be unsubstituted or substituted with one or two ormore halogen atoms.) These liquid crystal compounds may be used alone orin combination of two or more compounds.c) (Polymerization Initiator)

In the birefringent lens material for a stereoscopic image display ofthe present invention, a polymerization initiator may be used in orderto polymerize a liquid crystal compound having a polymerizablefunctional group. As a photopolymerization initiator used whenpolymerization is conducted by light irradiation, well-known, commonlyused photopolymerization initiators can be used.

Examples of the photopolymerization initiator include2-hydroxy-2-methyl-1-phenylpropan-1-one (“DAROCUR 1173” manufactured byMerck & Co., Inc.), 1-hydroxycyclohexyl phenyl ketone (“IRGACURE 184”manufactured by BASF),1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one (“DAROCUR 1116”manufactured by Merck & Co., Inc.),2-methyl-1-[(methylthio)phenyl]-2-morpholino propane-1 (“IRGACURE 907”manufactured by BASF), benzyl methyl ketal (“IRGACURE 651” manufacturedby BASF), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone(“IRGACURE 369” manufactured by BASF),2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)butan-1-one(“IRGACURE 379” manufactured by BASF),2,2-dimethoxy-1,2-diphenylethan-1-one,bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (DAROCUR TPO),2,4,6-trimethylbenzoyl-diphenylphosphine oxide (“IRGACURE 819”manufactured by BASF), 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)] (“IRGACURE OXE01” manufactured by BASF), ethanone,1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime)(“IRGACURE OXE02” manufactured by BASF), a mixture of2,4-diethylthioxanthone (“KAYACURE DETX” manufactured by Nippon KayakuCo., Ltd.) and ethyl p-dimethylamino benzoate (“KAYACURE EPA”manufactured by Nippon Kayaku Co., Ltd.), a mixture ofisopropylthioxanthone (“QUANTACURE ITX” manufactured by Ward BlenkinsopCo., Ltd.) and ethyl p-dimethylamino benzoate, and acylphosphine oxide(“Lucirin TPO” manufactured by BASF). The amount of photopolymerizationinitiator used is preferably 0.1% to 10% by mass, and particularlypreferably 0.5% to 5% by mass relative to the birefringent lens materialfor a stereoscopic image display. These may be used alone or incombination of two or more photopolymerization initiators.

As a thermal polymerization initiator used in the case of thermalpolymerization, well-known, commonly used thermal polymerizationinitiators can be used. Examples of the thermal polymerization initiatorthat can be used include organic peroxides such as methyl acetoacetateperoxide, cumene hydroperoxide, benzoyl peroxide,bis(4-t-butylcyclohexyl)peroxy dicarbonate, t-butylperoxy benzoate,methyl ethyl ketone peroxide,1,1-bis(t-hexylperoxy)3,3,5-trimethylcyclohexane, p-pentahydroperoxide,t-butyl hydroperoxide, dicumyl peroxide, isobutyl peroxide,di(3-methyl-3-methoxybutyl)peroxy dicarbonate, and1,1-bis(t-butylperoxy)cyclohexane; azonitrile compounds such as2,2′-azobisisobutyronitrile and 2,2′-azobis(2,4-dimethyl valeronitrile;azoamidine compounds such as2,2′-azobis(2-methyl-N-phenylpropione-amidine) dihydrochloride; azoamidecompounds such as2,2′-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propioneamide};and alkylazo compounds such as 2,2′-azobis(2,4,4-trimethylpentane). Theamount of thermal polymerization initiator used is preferably 0.1% to10% by mass, and particularly preferably 0.5% to 5% by mass relative tothe birefringent lens material for a stereoscopic image display. Thesemay be used alone or in combination of two or more thermalpolymerization initiators. These thermal polymerization initiators maybe used in combination with photopolymerization initiators.

d) (Polymerization Inhibitor)

In the birefringent lens material for a stereoscopic image display ofthe present invention, a polymerization inhibitor may be used in orderto stably produce or stably store the birefringent lens material.Examples of the polymerization inhibitor include phenolic compounds,quinone compounds, amine compounds, thioether compounds, and nitrosocompounds.

Examples of the phenolic compound include p-methoxyphenol, cresol,t-butyl catechol, 3,5-di-t-butyl-4-hydroxytoluene,2,2′-methylenebis(4-methyl-6-t-butylphenol),2,2′-methylenebis(4-ethyl-6-t-butylphenol),4,4′-thiobis(3-methyl-6-t-butylphenol), 4-methoxy-1-naphthol, and4,4′-dialkoxy-2,2′-bi-1-naphthol.

Examples of the quinone compound include hydroquinone,methylhydroquinone, tert-butyl hydroquinone, p-benzoquinone,methyl-p-benzoquinone, tert-butyl-p-benzoquinone,2,5-diphenylbenzoquinone, 2-hydroxy-1,4-naphthoquinone,1,4-naphthoquinone, 2,3-dichloro-1,4-naphthoquinone, anthraquinone, anddiphenoquinone.

Examples of the amine compound include p-phenylenediamine,4-aminodiphenylamine, N,N′-diphenyl-p-phenylenediamine,N-i-propyl-N′-phenyl-p-phenylenediamine,N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine,N,N′-di-2-naphthyl-p-phenylenediamine, diphenylamine,N-phenyl-β-naphthylamine, 4,4′-dicumyl-diphenylamine, and4,4′-dioctyl-diphenylamine.

Examples of the thioether compound include phenothiazine and distearylthiodipropionate.

Examples of the nitroso compound include N-nitrosodiphenylamine,N-nitrosophenylnaphthylamine, N-nitrosodinaphthylamine, p-nitrosophenol,nitrosobenzene, p-nitrosodiphenylamine, α-nitroso-β-naphthol etc.,N,N-dimethyl-p-nitrosoaniline, p-nitrosodiphenylamine,p-nitrosodimethylamine, p-nitroso-N,N-diethylamine,N-nitrosoethanolamine, N-nitrosodi-n-butylamine,N-nitroso-N-n-butyl-4-butanolamine, N-nitroso-diisopropanolamine,N-nitroso-N-ethyl-4-butanolamine, 5-nitroso-8-hydroxyquinoline,N-nitrosomorpholine, N-nitroso-N-phenylhydroxylamine ammonium salt,nitrosobenzene, 2,4,6-tri-tert-butylnitrosobenzene,N-nitroso-N-methyl-p-toluenesulfonamide, N-nitroso-N-ethylurethane,N-nitroso-N-n-propylurethane, 1-nitroso-2-naphthol,2-nitroso-1-naphthol, sodium 1-nitroso-2-naphthol-3,6-sulfonate, sodium2-nitroso-1-naphthol-4-sulfonate, 2-nitroso-5-methylaminophenolhydrochloride, and 2-nitroso-5-methylaminophenol hydrochloride.

e) (Stabilizer)

In the birefringent lens material for a stereoscopic image display ofthe present invention, a general-purpose stabilizer may be used for thepurpose of obtaining a coating film having a uniform thickness or forany other purposes. For example, additives such as a leveling agent, athixotropic agent, a surfactant, an ultraviolet absorber, an infraredabsorber, an antioxidant, and a surface treatment agent may be added tothe extent that the liquid-crystal alignment capability is notsignificantly decreased.

f) (Solvent)

In the birefringent lens material for a stereoscopic image display ofthe present invention, no solvent is usually used. However, a solventmay be used in order to uniformly apply the birefringent lens material.The solvent used is not particularly limited as long as a substrate oran alignment layer formed on the substrate is not dissoluted when thebirefringent lens material is applied onto the substrate and apolymerizable liquid crystal composition of the present invention can bealigned without defects. Solvents in which the polymerizable liquidcrystal compound exhibits good solubility are preferred. Examples ofsuch a solvent include aromatic hydrocarbons such as toluene, xylene,cumene, and mesitylene; ester solvents such as methyl acetate, ethylacetate, propyl acetate, and butyl acetate; ketone solvents such asmethyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethersolvents such as tetrahydrofuran, 1,2-dimethoxyethane, and anisole;amide solvents such as N,N-dimethylformamide and N-methyl-2-pyrrolidone;propylene glycol monomethyl ether acetate; diethylene glycol monomethylether acetate; γ-butyrolactone; and chlorobenzene. These may be usedalone or in combination of two or more solvents.

g) (Surfactant or Polymer that Promotes Homogeneous Alignment)

In the birefringent lens material for a stereoscopic image display ofthe present invention, a surfactant or polymer that promotes homogeneousalignment is used, as required, in the case where the state ofhomogeneous alignment is temporarily achieved by simply applying thebirefringent lens material in a process of producing a birefringent lensfor a stereoscopic image display.

The surfactant used is not particularly limited, but preferably asurfactant having a surface tension lower than that of a liquid crystalcompound having a polymerizable functional group. Examples of such asurfactant include fluorine-containing nonionic surfactants,organosilane surfactants, and polyacrylate surfactants. The surfactantsmay have a polymerizable group so that a stronger film is formed whenpolymerization is conducted.

The polymer used is not particularly limited, but preferably a polymerhaving a surface tension lower than that of a liquid crystal compoundhaving a polymerizable functional group. Examples of such a polymerinclude polyethylene, polypropylene, polyisobutylene, paraffin, liquidparaffin, chlorinated polypropylene, chlorinated paraffin, chlorinatedliquid paraffin, and polyvinylidene fluoride.The weight-average molecular weight of the polymer is preferably 200 to1,000,000, more preferably 300 to 100,000, and particularly preferably400 to 10,000.(Method for Producing Birefringent Lens for Stereoscopic Image Display)(Substrate)

A substrate used in a birefringent lens for a stereoscopic image displayof the present invention is a substrate that is usually used in liquidcrystal devices, displays, optical components, and optical films, and isnot particularly limited as long as the substrate has heat resistancethat can withstand heating after the birefringent lens material for astereoscopic image display of the present invention is applied or duringthe production of a liquid crystal device. Examples of the substrateinclude glass substrates, metal substrates, ceramic substrates, andplastic substrates. In particular, in the case where the substrate iscomposed of an organic material, examples of the organic materialinclude cellulose derivatives, polyolefins, polyesters, polycarbonates,polyacrylates, polyarylates, polyethersulfones, polyimides,polyphenylene sulfides, polyphenylene ethers, nylons, and polystyrenes.Among these, polyesters, polystyrenes, polyolefins, cellulosederivatives, polyarylates, and polycarbonates are preferable.

The substrate is usually subjected to an alignment treatment or analignment layer may be provided on the substrate so that thebirefringent lens material for a stereoscopic image display of thepresent invention is aligned when the birefringent lens material for astereoscopic image display is applied onto the substrate. Examples ofthe alignment treatment include a stretching treatment, a rubbingtreatment, a polarized ultraviolet-visible light irradiation treatment,and an ion-beam treatment. In the case where an alignment layer is used,well-known, commonly used alignment layers are used. Examples of thematerial of the alignment layer include compounds such as polyimides,polysiloxanes, polyamides, polyvinyl alcohols, polycarbonates,polystyrenes, polyphenylene ethers, polyarylates, polyethyleneterephthalates, polyethersulfones, epoxy resins, epoxy acrylate resins,acrylic resins, coumarin compounds, chalcon compounds, cinnamatecompounds, fulgide compounds, anthraquinone compounds, azo compounds,and arylethene compounds. Compounds that are subjected to an alignmenttreatment by rubbing are preferably materials, the crystallization ofwhich is accelerated by the alignment treatment or by performing aheating step after the alignment treatment. Among compounds that aresubjected to an alignment treatment other than rubbing, photo-alignmentmaterials are preferably used.

(Coating)

As a coating method for obtaining a birefringent lens for a stereoscopicimage display of the present invention, well-known, commonly usedmethods such as an applicator method, a bar coating method, a spincoating method, a gravure printing method, a flexographic printingmethod, an ink-jet method, a die coating method, a cap coating method,and dipping can be employed. In the case where a birefringent lensmaterial for a stereoscopic image display, the material being dilutedwith a solvent, is applied, the birefringent lens material is driedafter the application.

(Lens-Shaping Step)

Shaping of the birefringent lens for a stereoscopic image display of thepresent invention is performed by polymerizing a birefringent lensmaterial for a stereoscopic image display in the form of a lens by usinga photomask or covering a coating film of a birefringent lens materialfor a stereoscopic image display with a lens-shaped resin mold.

In the case where a photomask is used, a photomask that has a patterndesigned so that when the birefringent lens material for a stereoscopicimage display is polymerized, the resulting polymerized material has adesired lens shape is used. In the case where a resin mold is used, acoating film of a birefringent lens material for a stereoscopic imagedisplay is covered with a concave lens-shaped resin mold having arefractive index equal to an ordinary refractive index (no) of thebirefringent lens material for a stereoscopic image display of thepresent invention, and polymerization is conducted in this coveredstate. Alternatively, in the case where the resin mold is once detached,a resin used in the resin mold is applied onto the coating film of thebirefringent lens material for a stereoscopic image display, the coatingfilm having been taken from the resin mold, and polymerization is thenconducted.

(Polymerization Step)

A polymerization operation of the birefringent lens material for astereoscopic image display of the present invention is generallyperformed by irradiation with light such as ultraviolet light or byheating after the birefringent lens material for a stereoscopic imagedisplay is applied and the resulting coating film is formed into a lensshape. When the polymerization is conducted by light irradiation,specifically, the birefringent lens material is irradiated withpreferably ultraviolet light having a wavelength of 390 nm or less, andmost preferably light having a wavelength of 250 to 370 nm. However, inthe case where the polymerizable liquid crystal composition is, forexample, decomposed by ultraviolet light having a wavelength of 390 nmor less, in some cases, it is preferable to conduct the polymerizationtreatment with ultraviolet light having a wavelength of 390 nm or more.This light is preferably diffused light that is not polarized.

On the other hand, polymerization by heating is preferably conducted ata temperature at which the birefringent lens material for a stereoscopicimage display exhibits a liquid-crystalline phase or lower. Inparticular, when a thermal polymerization initiator that releasesradicals as a result of heating is used, it is preferable to use athermal polymerization initiator, the cleavage temperature of which iswithin the above temperature range. In the case where a thermalpolymerization initiator and a photopolymerization initiator are used incombination, the polymerization temperature and the respectiveinitiators are suitably selected, in addition to the consideration ofthe limitation of the above temperature range, so that the rates ofpolymerization of a photo-alignment layer and a polymerizable liquidcrystal film are not significantly different from each other. Thepolymerization is preferably conducted at a temperature lower than atemperature at which heterogeneous polymerization due to heat isinduced, though the heating temperature depends on the transitiontemperature from a liquid-crystalline phase to an isotropic phase of thepolymerizable liquid crystal composition. However, when the heatingtemperature exceeds a glass transition temperature of the substratecomposed of an organic material, thermal deformation of the substratebecomes significant. Thus, the heating temperature is preferably in therange of room temperature to the glass transition temperature of thesubstrate. For example, in the case where the polymerizable group is a(meth)acryloyl group, the polymerization is preferably conducted at atemperature lower than 90° C.

The birefringent lens for a stereoscopic image display may beheat-treated in order to stabilize solvent resistance and heatresistance of the resulting birefringent lens for a stereoscopic imagedisplay. In this case, heating is preferably conducted at a glasstransition temperature of the birefringent lens for a stereoscopic imagedisplay or higher. Usually, the heating is preferably conducted within arange that does not exceed the glass transition temperature of thesubstrate composed of an organic material. Alternatively, a lightirradiation treatment may be performed for the above purpose. In thiscase, it is preferable to perform the light irradiation treatment to theextent that the liquid crystal compound component in the birefringentlens for a stereoscopic image display is not subjected tophotodecomposition by the light irradiation.

The prepared birefringent lens for a stereoscopic image display may beused in integration with the substrate in the state where the substrateis left (refer to FIG. 2). Alternatively, the birefringent lens for astereoscopic image display may be separated from the substrate and usedin the state where the lens does not have a substrate (refer to FIG. 1).

EXAMPLES

The present invention will now be described by way of SynthesisExamples, Examples, and Comparative Examples. However, the presentinvention is not limited thereto. Note that “part” and “%” are on a massbasis unless otherwise specified.

(Preparation of Birefringent Lens Material (1) for Stereoscopic ImageDisplay)

Fifty parts of a liquid crystal compound represented by formula (B-1),50 parts of a liquid crystal compound represented by formula (B-2), 0.1parts of DAROCUR TPO (C-1), and 0.1 parts of p-methoxyphenol (D-1) weremixed while heating to prepare a birefringent lens material (1) for astereoscopic image display of the present invention.

(Preparation of Birefringent Lens Materials (2) to (20) for StereoscopicImage Display)

Birefringent lens materials (2) to (20) for a stereoscopic image displayof the present invention were prepared as in the preparation of thebirefringent lens material (1) for a stereoscopic image display of thepresent invention. Tables 1 to 5 show specific compositions of thebirefringent lens materials (1) to (20) for a stereoscopic image displayof the present invention.

TABLE 1 (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Compound (A-1) 50 20 10Compound (A-2) 50 10 Compound (A-3) 20 20 10 Compound (A-4) 20 20 15Compound (A-5) 20 20 15 Compound (B-1) 50 30 40 30 20 20 15 10 Compound(B-2) 50 30 40 30 20 20 15 10 Compound (B-3) 20 25 25 20 20 15 10Compound (B-4) 20 25 25 20 20 15 10 Compound (C-1) 0.1 0.1 0.1 0.1 0.10.1 0.1 0.1 0.1 0.1 Compound (C-2) Compound (C-3) Compound (D-1) 0.1 0.10.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Compound (D-2) Compound (E-1) Compound(E-2) Compound (F-1)

TABLE 2 (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) Compound (A-1)15 15 15 10 15 Compound (A-2) Compound (A-3) 15 15 15 15 15 Compound(A-4) 10 10 10 10 10 20 Compound (A-5) 10 10 10 10 10 20 Compound (B-1)15 15 15 15 15 20 100 Compound (B-2) 15 15 15 15 15 20 100 Compound(B-3) 10 10 10 10 10 10 100 Compound (B-4) 10 10 10 10 10 10 100Compound (C-1) 0.1 0.1 0.1 0.1 0.1 0.1 Compound (C-2) 1 1 Compound (C-3)1 3 Compound (D-1) 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Compound (D-2)0.1 Compound (E-1) 5 Compound (E-2) 0.2 Compound (F-1) 150

IRGACURE 651 (C-2) (manufactured by BASF)IRGACURE 907 (C-3) (manufactured by BASF)Quino Power LSN (D-2) (manufactured by Kawasaki Kasei Chemicals Ltd.)Butyl acrylate (E-1) (manufactured by Toagosei Co., Ltd.)IRGANOX 1076 (E-2) (manufactured by BASF)Cyclopentanone (F-1)

Example 1

A polyimide solution for an alignment layer was applied onto a glasssubstrate having a thickness of 0.7 mm by a spin coating method. Thepolyimide solution was dried at 100° C. for 10 minutes and then baked at200° C. for 60 minutes to obtain a coating film. The coating film wassubjected to a rubbing treatment. The rubbing treatment was conductedusing a commercially available rubbing device.

The birefringent lens material (1) for a stereoscopic image display ofthe present invention was applied onto the rubbed substrate by a spincoating method in the state where the birefringent lens material (1) washeated at 80° C. Another substrate that had been subjected to a rubbingtreatment was arranged on the resulting coating film so that the rubbingdirection of the other substrate is antiparallel to the above-describedsubstrate, and the resulting product was then cooled to roomtemperature. Subsequently, the product was irradiated with UV light atan intensity of 40 mW/cm² for 25 seconds using a high-pressuremercury-vapor lamp. The cured coating film was then separated from therubbed substrates, thus obtaining a cured product of the birefringentlens material for a stereoscopic image display of the present invention.The cured product had a film thickness of 50 μm, an ordinary refractiveindex no of 1.537, an extraordinary refractive index ne of 1.701, and aΔn of 0.165. The alignment of the cured product was also good. Thetransition temperature from a solid phase to a liquid-crystalline phasewas −21° C., and the transition temperature from a liquid-crystallinephase to a liquid phase was 121° C.

Examples 2 to 14

Cured products of the birefringent lens materials for a stereoscopicimage display of the invention in Examples 2 to 14 were obtained as inExample 1. Each of the cured products had a film thickness of 50 μm, andthe alignment thereof was good. The obtained results are shown in Table3.

Each of the birefringent lens materials for a stereoscopic image displayof the present invention can be polymerized at room temperature, has agood alignment property, and is good in terms of productivity.

TABLE 3 Transition Transition Coating Alignment temperature temperatureBirefringent lens material for temperature at room (solid/ (liquidstereoscopic image display (° C.) temperature ne no Δn liquid crystal)crystal/liquid) Example 1 Birefringent lens material (1) 80 Good 1.7011.537 0.164 −21° C. 121° C.  for stereoscopic image display Example 2Birefringent lens material (2) 70 Good 1.695 1.533 0.162 −25° C. 95° C.for stereoscopic image display Example 3 Birefringent lens material (3)40 Good 1.595 1.543 0.052 −30° C. 53° C. for stereoscopic image displayExample 4 Birefringent lens material (4) 40 Good 1.646 1.544 0.102 −31°C. 52° C. for stereoscopic image display Example 5 Birefringent lensmaterial (5) 70 Good 1.699 1.531 0.168 −25° C. 90° C. for stereoscopicimage display Example 6 Birefringent lens material (6) 70 Good 1.6941.526 0.168 −21° C. 125° C.  for stereoscopic image display Example 7Birefringent lens material (7) 70 Good 1.672 1.535 0.137 −21° C. 86° C.for stereoscopic image display Example 8 Birefringent lens material (8)70 Good 1.697 1.531 0.166 −28° C. 75° C. for stereoscopic image displayExample 9 Birefringent lens material (9) 70 Good 1.701 1.533 0.168 −26°C. 98° C. for stereoscopic image display Example 10 Birefringent lensmaterial (10) 70 Good 1.676 1.531 0.145 −29° C. 80° C. for stereoscopicimage display Example 11 Birefringent lens material (11) 70 Good 1.6891.533 0.156 −28° C. 85° C. for stereoscopic image display Example 12Birefringent lens material (12) 70 Good 1.689 1.533 0.156 −28° C. 85° C.for stereoscopic image display Example 13 Birefringent lens material(13) 70 Good 1.689 1.533 0.156 −28° C. 85° C. for stereoscopic imagedisplay Example 14 Birefringent lens material (14) 70 Good 1.689 1.5330.156 −27° C. 70° C. for stereoscopic image display

Comparative Examples 1 to 4

Cured products of the birefringent lens materials for a stereoscopicimage display in Comparative Examples 1 to 4 were obtained as inExample 1. In each of the cured products, crystallization significantlyoccurred when polymerization was conducted at room temperature, and alarge number of alignment defects were observed. The obtained resultsare shown in Table 4.

TABLE 4 Transition Transition Coating Alignment temperature temperatureBirefringent lens material for temperature at room (solid/ (liquidstereoscopic image display (° C.) temperature ne no Δn liquid crystal)crystal/liquid) Comparative Birefringent lens material (17) 80 Defectswere 1.707 1.533 0.174 69° C. 128° C. Example 1 for stereoscopic imagedisplay observed Comparative Birefringent lens material (18) 80 Defectswere 1.700 1.530 0.170 63° C. 124° C. Example 2 for stereoscopic imagedisplay observed Comparative Birefringent lens material (19) 80 Defectswere — — — —  67° C. Example 3 for stereoscopic image display observedComparative Birefringent lens material (20) 80 Defects were 1.670 1.5270.143 63° C.  81° C. Example 4 for stereoscopic image display observed

Example 15

A polyimide solution for an alignment layer was applied onto a glasssubstrate having a thickness of 0.7 mm by a spin coating method. Thepolyimide solution was dried at 100° C. for 10 minutes and then baked at200° C. for 60 minutes to obtain a coating film. The coating film wassubjected to a rubbing treatment. The rubbing treatment was conductedusing a commercially available rubbing device.

The birefringent lens material (15) for a stereoscopic image display ofthe present invention was applied onto the rubbed substrate 3 by a spincoating method in the state where the birefringent lens material (15)was heated at 70° C. A resin mold 1 that had been subjected to analignment treatment was arranged on the resulting coating film so thatan alignment direction of the rubbed substrate was parallel to analignment direction of the resin mold 1, and the resulting product wasthen cooled to room temperature. Subsequently, the product wasirradiated with ultraviolet light at an intensity of 40 mW/cm² for 25seconds using a high-pressure mercury-vapor lamp. Thus, a birefringentlens for a stereoscopic image display was obtained. The substrate 3 wasdetached from the obtained lens to produce a birefringent lens for astereoscopic image display illustrated in FIG. 1. The obtainedbirefringent lens for a stereoscopic image display of the presentinvention had no defect, and the alignment of the birefringent lens wasalso good. The birefringent lens material (15) for a stereoscopic imagedisplay of the present invention had a transition temperature from asolid phase to a liquid-crystalline phase of −25° C. and a transitiontemperature from a liquid-crystalline phase to a liquid phase of 87° C.

Example 16

A polyimide solution for an alignment layer was applied onto a glasssubstrate having a thickness of 0.7 mm by a spin coating method. Thepolyimide solution was dried at 100° C. for 10 minutes and then baked at200° C. for 60 minutes to obtain a coating film. The coating film wassubjected to a rubbing treatment. The rubbing treatment was conductedusing a commercially available rubbing device.

The birefringent lens material (15) for a stereoscopic image display ofthe present invention was applied onto the rubbed substrate 3 by a spincoating method in the state where the birefringent lens material (15)was heated at 70° C. A resin mold 1 that had been subjected to analignment treatment was arranged on the resulting coating film so thatan alignment direction of the rubbed substrate was parallel to analignment direction of the resin mold 1, and the resulting product wasthen cooled to room temperature. Next, the resin mold 1 was slowlydetached, and an ultraviolet-curable epoxy acrylate resin was appliedonto the coating film by a spin coating method. Subsequently, theresulting product was irradiated with ultraviolet light at an intensityof 40 mW/cm² for 25 seconds using a high-pressure mercury-vapor lamp.Thus, a birefringent lens for a stereoscopic image display illustratedin FIG. 2 was obtained. The obtained birefringent lens for astereoscopic image display of the present invention had no defect, andthe alignment of the birefringent lens was also good.

Example 17

A polyimide solution for an alignment layer was applied onto a glasssubstrate having a thickness of 0.7 mm by a spin coating method. Thepolyimide solution was dried at 100° C. for 10 minutes and then baked at200° C. for 60 minutes to obtain a coating film. The coating film wassubjected to a rubbing treatment. The rubbing treatment was conductedusing a commercially available rubbing device.

Next, 0.2 parts of liquid paraffin was added to 100 parts of thebirefringent lens material (16) for a stereoscopic image display, andthe mixture was then applied onto the rubbed substrate by a spin coatingmethod in an atmosphere at room temperature. The resulting coating filmwas dried at 80° C. for 10 minutes, and then irradiated with ultravioletlight through a mask having a pattern. The ultraviolet irradiation wasperformed at an intensity of 40 mW/cm² for 25 seconds using ahigh-pressure mercury-vapor lamp. The resulting cured film was washedwith propylene glycol monomethyl ether acetate for one minute to removeuncured portions. An ultraviolet-curable epoxy acrylate resin wasfurther applied by a spin coating method. Subsequently, the resultingproduct was irradiated with ultraviolet light at an intensity of 40mW/cm² for 25 seconds using a high-pressure mercury-vapor lamp. Thus, abirefringent lens for a stereoscopic image display illustrated in FIG. 2was obtained. The obtained birefringent lens for a stereoscopic imagedisplay of the present invention had no defect, and the alignment of thebirefringent lens was also good. In the components except forcyclopentanone in the birefringent lens material (16) for a stereoscopicimage display, the transition temperature from a solid phase to aliquid-crystalline phase was −26° C. and the transition temperature froma liquid-crystalline phase to a liquid phase was 96° C.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a structure of a birefringent lens for a stereoscopicimage display of the present invention.

FIG. 2 illustrates a structure of a birefringent lens (including asubstrate) for a stereoscopic image display of the present invention.

REFERENCE SIGNS LIST

-   -   1: resin mold    -   2: birefringent lens    -   3: substrate

The invention claimed is:
 1. A birefringent lens material for preparinga birefringent lens for a stereoscopic image display, comprising; afirst liquid crystal compound having two polymerizable functionalgroups; a second liquid crystal compound having two polymerizablefunctional groups, and a third crystal compound having one polymerizablefunctional group, wherein each of the first liquid crystal compound, thesecond liquid crystal compound and the third liquid crystal compound isa compound represented by general formula (1):P¹-(Sp)_(m)-MG-R¹  (1) where P¹ represents a polymerizable functionalgroup; Sp represents a spacer group having 0 to 18 carbon atoms; mrepresents 0 or 1; MG represents a mesogenic group or a mesogenitysupporting group; and R¹ of the third liquid crystal compound representsa halogen atom, a cyano group, a thiocyanate group, a hydroxy group, anNCO group, an OCN group, or an alkyl group having 1 to 18 carbon atoms,the alkyl group may be substituted with at least one selected fromhalogen atoms, a cyano group, and a hydroxy group, and one CH₂ group ortwo or more non-adjacent CH₂ groups present in this group may each beindependently substituted with a divalent organic group selected fromthe group consisting of —O—, —S—, —NH—, —N(CH₃)—, —CO—, —COO—, —OCO—,—OCOO—, —SCO—, —COS—, —CH═CH—, and —C≡C— in such a manner that oxygenatoms are not directly bonded to each other, and R¹ of the first andsecond liquid crystal compounds represents a structure represented bygeneral formula (1-a):-(Sp)_(m)-P²  (1-a) where P² represents a polymerizable functionalgroup, Sp represents a spacer group having 0 to 18 carbon atoms, and mrepresents 0 or 1; wherein the birefringent lens material has atransition temperature from a solid phase to a liquid-crystalline phaseof −10° C. or lower and a transition temperature from aliquid-crystalline phase to a liquid phase of 50° C. or higher.
 2. Thebirefringent lens material according to claim 1, wherein thebirefringent lens material can be polymerized at room temperature. 3.The birefringent lens material according to claim 1, wherein MG of thefirst liquid crystal compound is the same as that of the second liquidcrystal compound.
 4. The birefringent lens material according to claim3, further comprising: a fourth liquid crystal compound having onepolymerizable functional group wherein the fourth liquid crystalcompound is a compound represented by said general formula (1), whereinMG of the third liquid crystal compound is the same as that of thefourth liquid crystal compound, wherein MG of the first liquid crystalcompound is the same as that of the second liquid crystal compound. 5.The birefringent lens material according to claim 1, wherein, in generalformula (1), Sp represents a single bond or an alkylene group (where thealkylene group may be substituted with at least one selected fromhalogen atoms and CN, and one CH₂ group or two or more non-adjacent CH₂groups present in this group may each be independently substituted with—O—, —S—, —NH—, —N(CH₃)—, —CO—, —COO—, —OCO—, —OCOO—, —SCO—, —COS—,—CONH—, —NHCO—, —CH═CH—, or —C≡C— in such a manner that oxygen atoms arenot directly bonded to each other), and MG is represented by generalformula (1-b):—Z0-(A1-Z1)_(n)-A2-Z2-A3-Z3-  (1-b) where A1, A2, and A3 eachindependently represent a 1,4-phenylene group, a 1,4-cyclohexylenegroup, a 1,4-cyclohexenyl group, a tetrahydropyran-2,5-diyl group, a1,3-dioxane-2,5-diyl group, a tetrahydrothiopyran-2,5-diyl group, a1,4-bicyclo[2.2.2]octylene group, a decahydronaphthalene-2,6-diyl group,a pyridine-2,5-diyl group, a pyrimidine-2,5-diyl group, apyrazine-2,5-diyl group, a thiophene-2,5-diyl group, a1,2,3,4-tetrahydronaphthalene-2,6-diyl group, a 1,4-naphthylene group, a1,5-naphthylene group, a 1,6-naphthylene group, a 2,6-naphthylene group,a phenanthrene-2,7-diyl group, a 9,10-dihydrophenanthrene-2,7-diylgroup, a 1,2,3,4,4a,9,10a-octahydrophenanthrene-2,7-diyl group, abenzo[1,2-b:4,5-b′]dithiophene-2,6-diyl group, abenzo[1,2-b:4,5-b′]diselenophene-2,6-diyl group, a[1]benzothieno[3,2-b]thiophene-2,7-diyl group, a[1]benzoselenopheno[3,2-b]selenophene-2,7-diyl group, or afluorene-2,7-diyl group, and may have, as at least one substituent, atleast one selected from F, Cl, CF₃, OCF₃, a CN group, alkyl groups eachhaving 1 to 8 carbon atoms, alkoxy groups each having 1 to 8 carbonatoms, alkanoyl groups each having 1 to 8 carbon atoms, alkanoyloxygroups each having 1 to 8 carbon atoms, alkenyl groups each having 2 to8 carbon atoms, alkenyloxy groups each having 2 to 8 carbon atoms,alkenoyl groups each having 2 to 8 carbon atoms, and alkenoyloxy groupseach having 2 to 8 carbon atoms; Z0, Z1, Z2, and Z3 each independentlyrepresent —COO—, —OCO—, —CH₂CH₂—, —OCH₂—, —CH₂O—, —CH═CH—, —C≡C—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—,—OCOCH₂CH₂—, —CONH—, —NHCO—, an alkylene group which has 2 to 10 carbonatoms and which may have a halogen atom, or a single bond; and nrepresents 0, 1, or
 2. 6. The birefringent lens material according toclaim 1, wherein, in general formula (1), P¹ represents a substituentselected from the group consisting of substituents represented bygeneral formulae (P-1) to (P-18):


7. The birefringent lens material according to claim 1, comprising acompound selected from the compound group represented by generalformulae (2a) and (2b):

where Z¹⁰ and Z¹¹ each independently represent a hydrogen atom or amethyl group; m and m1 represent 0 or 1; W¹, W¹¹, W², and W¹² eachindependently represent a single bond, —O—, —COO—, or —OCO—; Y⁰, Y¹, Y²,and Y¹¹ each independently represent —COO— or —OCO—; r, r1, s, and s1each independently represent an integer of 2 to 18; and a 1,4-phenylenegroup present in the formulae may be substituted with at least oneselected from alkyl groups each having 1 to 7 carbon atoms, alkoxygroups each having 1 to 7 carbon atoms, alkanoyl groups each having 1 to7 carbon atoms, a cyano group, and halogen atoms.
 8. The birefringentlens material according to claim 1, comprising a compound selected fromthe compound group represented by general formulae (3) and (4):

where Z¹ and Z³ each independently represent a hydrogen atom, a halogenatom, a cyano group, or a hydrocarbon group having 1 to 18 carbon atoms;Z² and Z⁴ each independently represent a hydrogen atom or a methylgroup; t and u each independently represent 0, 1, or 2; v represents aninteger of 2 to 18; W³ represents a single bond, —O—, —COO—, or —OCO—;A, B, C, D, E, and F each independently represent a 1,4-phenylene group,a 1,4-phenylene group in which non-adjacent CH groups are eachsubstituted with nitrogen, a 1,4-cyclohexylene group, a1,4-cyclohexylene group in which one or non-adjacent two CH₂ groups areeach substituted with an oxygen or sulfur atom, a 1,4-cyclohexenylgroup, a 1,4-bicyclo[2.2.2]octylene group, adecahydronaphthalene-2,6-diyl group, a pyridine-2,5-diyl group, apyrimidine-2,5-diyl group, a pyrazine-2,5-diyl group, a1,2,3,4-tetrahydronaphthalene-2,6-diyl group, a 2,6-naphthylene group,or a 1,4-naphthylene group, and a 1,4-phenylene group and a2,6-naphthylene group that are present in the formulae may each besubstituted with at least one selected from alkyl groups each having 1to 7 carbon atoms, alkoxy groups each having 1 to 7 carbon atoms,alkanoyl groups each having 1 to 7 carbon atoms, a cyano group, andhalogen atoms; Y³, Y⁴, Y⁶, and Y⁷ each independently represent a singlebond, —CH₂CH₂—, —CH₂O—, —OCH₂—, —COO—, —OCO—, —C≡C—, —CH═CH—, —CF═CF—,—(CH₂)₄—, —CH₂CH₂CH₂O—, —OCH₂CH₂CH₂—, —CH═CHCH₂CH₂—, —CH₂CH₂CH═CH—,—CH═CHCOO—, —OCOCH═CH—, —CH₂CH₂COO—, —CH₂CH₂OCO—, —COOCH₂CH₂—, or—OCOCH₂CH₂—; and Y⁵ and Y⁸ each independently represent a single bond,—O—, —COO—, —OCO—, or —CH═CHCOO—.